The invention relates to a drive configuration for stair lifts. The drive configuration has a load-bearing configuration which is mounted displaceably on a first (bottom) guide rail and a second (top) guide rail, and has a drive device interacting with a drive rail.
German Patent DE 42 11 870 C1 discloses a drive configuration of the generic type in which the propelling force is transmitted to a drive member of rectangular cross section via drive rollers. This driving takes place in an exclusively force-fitting manner. In order to achieve the necessary propelling force with permissible contact pressures here, four drive rollers are necessary. This results in a problem of rollers being constrained over curves of the drive member.
It has been found, in practice, that two rollers acting in a force-fitting manner are not sufficient. European Patent EP 0 525 141 and German Utility Model DE-U-9211115 describe purely force-fitting drives in which separate pairs of rollers act on bottom and top tubular guides. In this case, high forces in the case of a possible low coefficient of friction of 0.1 (when wet) in the steel/steel material pairing and the running rollers butting against the tubular guide all the way around are disadvantageous. A purely roaming operation is only present at the smallest roller diameter, sliding taking place between the rollers and tube at the flanks, and this sliding, even in the case of tubular guides made of stainless steel, results in the formation of grooves and ridges, which may cause injury since the top tubular guide is also used as a handrail.
Furthermore, the lift-construction regulations do not allow any monitoring of speed, which is necessary for an arresting mechanism, by force fitting without additional measures, for example an electronic slippage-monitoring device, which gives rise to additional costs.
It is accordingly an object of the invention to provide a drive configuration for stair lifts that overcomes the above-mentioned disadvantages of the prior art devices of this general type, in which the tubular guides which are also used as a handrail are not subjected to any excessive contact pressure by drive rollers.
With the foregoing and other objects in view there is provided, in accordance with the invention, a drive configuration for stair lifts. The drive configuration contains a load-bearing configuration which is to be mounted displaceably on guide rails including a first guide rail and a second guide rail. A drive rail having engagement openings formed therein and spaced apart at regular intervals in a longitudinal direction is provided. A drive unit interacts with the drive rail and is supported by the load-bearing configuration. The drive unit has two gearwheel-shaped drive wheels disposed opposite one another and accommodate the drive rail with a contact-pressure force acting on the drive wheels to engage the drive rail. The drive wheels have radially projecting drive protrusions interacting with the engagement openings in a form-fitting drive connection.
The object is achieved according to the invention by a drive configuration for stair lifts, having the load-bearing configuration which is mounted displaceably on a first (bottom) guide rail and a second (top) guide rail. The drive configuration further has a drive unit interacting with a drive rail, which is distinguished in that the drive rail has engagement openings spaced apart at regular intervals in the longitudinal direction. The drive unit has two gearwheel-like drive wheels which are disposed opposite one another, accommodate the drive rail, with a radial contact-pressure force, between them and have radially projecting drive protrusions. The drive protrusions interact with the engagement openings in a form-fitting drive connection and the drive surfaces interact with running surfaces in a force-fitting drive connection.
The invention also relates to a stair lift having a drive configuration according to the invention.
In accordance with an added feature of the invention, the drive rail is a perforated bar having the engagement openings formed therein and two uninterrupted, mutually opposite running surfaces. The drive wheels have drive surfaces which are uninterrupted in a circumferential direction and interact with the running surfaces in a force-fitting drive connection.
In accordance with an additional feature of the invention, the drive rail having the engagement openings is a groove bar with grooves formed therein and spaced apart at regular intervals in the longitudinal direction.
In accordance with another feature of the invention, the drive rail has a given thickness and the drive protrusions have a radial length corresponding approximately to half of the given thickness of the drive rail. The drive protrusions are bolts inserted into the drive wheels. In addition, the drive protrusions on the drive wheels are spaced apart by an angle of 20xc2x0 in a circumferential direction.
In accordance with a further feature of the invention, the perforated bar has in each case one of the running surfaces disposed on each side of the engagement openings, and the drive wheels have in each case one of the drive surfaces on each side of the drive protrusions.
In accordance with another added feature of the invention, the perforated bar is produced from a flat steel bar and the engagement openings are punched.
In accordance with another additional feature of the invention, a pressure assembly having springs for producing an adjustable contact-pressure force being the contact pressure force exerted on the drive wheels is provided.
In accordance with another further feature of the invention, the drive unit has inter-engaging coupling gearwheels and shafts. Each of the drive wheels is mounted on one of the shafts, and the shafts are parallel to each other and connected in a rotationally fixed manner to the inter-engaging coupling gearwheels.
In accordance with a further added feature of the invention, the drive rail is retained at a fixed spacing from the guide rails and is fitted such that it is angle-adjustable and height-adjustable.
In accordance with a further additional feature of the invention, the drive protrusions are in a form of truncated cones and the engagement openings are in a form of double truncated cones.
In accordance with an added feature of the invention, the drive rail is to be retained on uprights which are disposed between the guide rails.
In accordance with an additional feature of the invention, a carrying frame which bears a load which is to be transported is mounted in a vertically displaceable manner on the load-bearing configuration. A housing carrying the drive wheels is retained pivotably on the carrying frame, and with a progression of the drive wheels along the drive rail, the housing defines a height position of the carrying frame relative to the load-bearing configuration.
In accordance with another feature of the invention, in an end region of the guide rails, the drive rail is guided in a direction of the first guide rail.
In accordance with a further feature of the invention, the load-bearing configuration has guide rollers and is guided on the guide rails in each case by two of the guide rollers.
In accordance with another added feature of the invention, a drive motor is fixed on the carrying frame and has a gear mechanism.
In accordance with another additional feature of the invention, a carrying frame bearing a load which is to be carried is mounted in a vertically displaceable manner on the load-bearing configuration. The drive wheels are mounted on the load-bearing configuration and the carrying frame has at least one carrying roller and is guided and supported on one of the guide rails by way of the at least one carrying roller. A drive motor is disposed on the carrying frame. A chain wheel is connected in a rotationally fixed manner to one of the drive wheels. A first deflecting wheel is disposed on the load-bearing configuration and a second deflecting wheel is disposed on the carrying frame. An endless drive chain drives one of the drive wheels. The endless drive chain is guided in each case over the first deflecting wheel and the second deflecting wheel, so that, during operation of the drive configuration, tractive chain forces result in a vertically upwardly directed raising force between the load-bearing configuration and the carrying frame.
In accordance with another further feature of the invention, the load-bearing configuration is guided and supported on the second guide rail and on the perforated bar. The drive rail is disposed at a fixed spacing beneath the second guide rail.
In accordance with an added feature of the invention, the carrying frame is to be supported on the first guide rail, the first guide rail is to be disposed at one of a predeterminable and adjustable, locally different spacing from the second guide rail and the drive rail. As a result of which it is possible to predetermine a local vertical position of the carrying frame relative to the load-bearing configuration.
In accordance with an additional feature of the invention, the carrying frame is to be supported on the first guide rail by at least one carrying roller.
In accordance with another feature of the invention, the load-bearing configuration has a pair of rollers for supporting the load-bearing configuration on the second guide rail.
In accordance with a further feature of the invention, the carrying frame has a top region and the drive motor is disposed in the top region of the carrying frame.
In accordance with another added feature of the invention, a drive chain wheel is driven by the drive motor. The endless drive chain is routed to the second deflecting wheel, and, from there, to the first deflecting wheel and, from there, to the chain wheel and back to the drive chain wheel.
In accordance with another additional feature of the invention, a platform for transporting a transportable load is disposed on the carrying frame.
In accordance with a concomitant feature of the invention, the drive rail is retained at locally different spacings from the guide rails and is fitted such that it is angle-adjustable and height-adjustable.
Other features which are considered as characteristic for the invention are set forth in the appended claims.
Although the invention is illustrated and described herein as embodied in a drive configuration for stair lifts, it is nevertheless not intended to be limited to the details shown, since various modifications and structural changes may be made therein without departing from the spirit of the invention and within the scope and range of equivalents of the claims.
The construction and method of operation of the invention, however, together with additional objects and advantages thereof will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings.